Precision Piezo Orion react late...

because for a few days I am having problems with the sensor, Precision Piezo. Until yesterday it worked, PERFECT, but a couple of days ago I got some failure, I explain:

Hardware that I use.

TLM printer

Duet plate

Extruder Prometheus v2.

Precision Piezo Orion

The problem....

When I give it to calibrate, or to make the Heightmap for the compensation, the same problem, in 75% of the surface of the base the test points work perfectly, with a soft touch ... but in 25%, maybe less, which corresponds to a quadrant of the base, you hear a hard hit (Hard Tap).

If I try PPO (Precision Piezo Orion), hitting the nozzle gently with an object, it detects the object, but in that area of ​​the bed, it seems as if it takes longer to react.

Before this, when it came out the summary of the calibration, the deviation was VERY low, 0.1 mm, since I happened this has risen to 0.35 mm approx.

I'm using PPO, this way in config.g

M558 P8 I1 R0.4 F300 X0 Y0 Z0
G31 X0 Y0 Z-0.1 P100

But I have tried like M558 P5, and similar, even more strong touches.

Any idea of ​​what I can do.

I HAVE NOT TOUCHED THE POTENTIOMETER OF HOW IT COMES, TO WHICH AT THE BEGINNING I WORKED PERFECT.